1. Field of the Invention
The present invention relates to a character pattern generation apparatus for producing dots based on outline data indicative of a contour of a character or a figure, and more particularly to a character pattern generation apparatus suitably used for a serial printer which prints a piece of outline data by a plurality of printing passes.
2. Prior Art
An outline font has various advantages in that, since a character or a pattern to be printed is stored in the form of its contour data, the amount of memory capacity can be reduced to store the data as compared with bit map data representing a character or a pattern by dots, and in that the quality of a printed character is not deteriorated even when the size of the character is reduced or magnified.
When a serial printer prints a pattern which is spread over an area greater than a width of a printing pass, the serial printer performs a plurality of printing passes to complete the printing of the pattern while feeding a sheet in such a manner that the interline space is zero.
When a figure which is indicated by an outline font is printed by the above-mentioned printing method, coordinates of reference points constituting the outline font are converted into coordinate values in accordance with a degree of magnification which is designated by attribute data. The coordinate values are converted into bit map data. Then, only bit data which correspond to a first printing pass are extracted, and the printing is performed for the first printing pass. Then, bit map data in accordance with the degree of magnification are generated from the same outline data in the same manner as described above, and only bit data corresponding to a second printing pass are extracted, and then the printing for the second printing pass is performed. The above process is sequentially repeated.
As described above, bit map data in accordance with a degree of magnification designated by attribute data are generated for each printing pass. Then, only the part of bit data which corresponds to the current printing pass is segmented. Therefore, the operation of converting the outline font data into bit data is required even for a portion not related to the printing, with the result that it takes a prolonged period of time to output bit map data. Moreover, in order to store bit data for all the area of the magnified character, a memory having a large capacity is required.